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 #include <QtGui>

 #include "codeeditor.h"


 CodeEditor::CodeEditor(QWidget *parent) : QPlainTextEdit(parent)
 {
	 lineNumberArea = new LineNumberArea(this);

	 connect(this, SIGNAL(blockCountChanged(int)), this, SLOT(updateLineNumberAreaWidth(int)));
	 connect(this, SIGNAL(updateRequest(QRect,int)), this, SLOT(updateLineNumberArea(QRect,int)));
	 //connect(this, SIGNAL(cursorPositionChanged()), this, SLOT(highlightCurrentLine()));

	 updateLineNumberAreaWidth(0);
	 //highlightCurrentLine();
 }



 int CodeEditor::lineNumberAreaWidth()
 {
	 int digits = 1;
	 int max = qMax(1, blockCount());
	 while (max >= 10) {
		 max /= 10;
		 ++digits;
	 }

	 int space = 3 + fontMetrics().width(QLatin1Char('9')) * digits;

	 return space;
 }



 void CodeEditor::updateLineNumberAreaWidth(int /* newBlockCount */)
 {
	 setViewportMargins(lineNumberAreaWidth(), 0, 0, 0);
 }



 void CodeEditor::updateLineNumberArea(const QRect &rect, int dy)
 {
	 if (dy)
		 lineNumberArea->scroll(0, dy);
	 else
		 lineNumberArea->update(0, rect.y(), lineNumberArea->width(), rect.height());

	 if (rect.contains(viewport()->rect()))
		 updateLineNumberAreaWidth(0);
 }



 void CodeEditor::resizeEvent(QResizeEvent *e)
 {
	 QPlainTextEdit::resizeEvent(e);

	 QRect cr = contentsRect();
	 lineNumberArea->setGeometry(QRect(cr.left(), cr.top(), lineNumberAreaWidth(), cr.height()));
 }



 void CodeEditor::highlightCurrentLine()
 {
	 QList<QTextEdit::ExtraSelection> extraSelections;

	 if (!isReadOnly()) {
		 QTextEdit::ExtraSelection selection;

		 QColor lineColor = QColor(Qt::yellow).lighter(160);

		 selection.format.setBackground(lineColor);
		 selection.format.setProperty(QTextFormat::FullWidthSelection, true);
		 selection.cursor = textCursor();
		 selection.cursor.clearSelection();
		 extraSelections.append(selection);
	 }

	 setExtraSelections(extraSelections);
 }


 void CodeEditor::highlightLine(int line)
 {
	 QList<QTextEdit::ExtraSelection> extraSelections;

	 if (!isReadOnly()) {
		 QTextEdit::ExtraSelection selection;

		 QColor lineColor = QColor(Qt::red);

		 selection.format.setForeground(lineColor);
		 selection.format.setProperty(QTextFormat::FullWidthSelection, true);
		 selection.cursor = QTextCursor(document()->findBlockByLineNumber(line));
		 extraSelections.append(selection);
	 }

	 setExtraSelections(extraSelections);
 }

 void CodeEditor::lineNumberAreaPaintEvent(QPaintEvent *event)
 {
	 QPainter painter(lineNumberArea);
	 painter.fillRect(event->rect(), Qt::lightGray);


	 QTextBlock block = firstVisibleBlock();
	 int blockNumber = block.blockNumber();
	 int top = (int) blockBoundingGeometry(block).translated(contentOffset()).top();
	 int bottom = top + (int) blockBoundingRect(block).height();

	 while (block.isValid() && top <= event->rect().bottom()) {
		 if (block.isVisible() && bottom >= event->rect().top()) {
			 QString number = QString::number(blockNumber + 1);
			 painter.setPen(Qt::black);
			 painter.drawText(0, top, lineNumberArea->width(), fontMetrics().height(),
							  Qt::AlignRight, number);
		 }

		 block = block.next();
		 top = bottom;
		 bottom = top + (int) blockBoundingRect(block).height();
		 ++blockNumber;
	 }
 }
